This invention relates generally to systems and methods for moving a headrest of a vehicular seat to protect an occupant in a crash and more particularly, to systems and methods for moving a headrest based on anticipatory sensing of a crash to protect the occupant in the crash.
Approximately 100,000 rear impacts per year result in whiplash injuries to the vehicle occupants. Most of these injuries could be prevented if the headrest were properly positioned behind the head of the occupant and if it had the correct contour to properly support the head and neck of the occupant. Whiplash injuries are the most expensive automobile accident injury even though these injuries are usually are not life threatening and are usually classified as minor.
A good discussion of the causes of whiplash injuries in motor vehicle accidents can be found in Dellanno et al, U.S. Pat. Nos. 5,181,763 and 5,290,091, and Dellanno, U.S. Pat. Nos. 5,580,124, 5,769,489 and 5,961,182, which are incorporated herein by reference, as well as many other technical papers. These patents discuss a novel automatic adjustable headrest to minimize such injuries. However, these patents assume that the headrest is properly positioned relative to the head of the occupant. A survey has shown that as many as 95% of automobiles do not have the headrest properly positioned. These patents also assume that all occupants have approximately the same contour of the neck and head. Observations of humans, on the other hand, show that significant differences occur where the back of some people""s heads is almost in the same plane as the that of their neck and shoulders, while other people have substantially the opposite case, that is, their neck extends significantly forward of their head back and shoulders
One proposed attempt at solving the problem where the headrest is not properly positioned uses a conventional crash sensor which senses the crash after impact and a headrest composed of two portions, a fixed portion and a movable portion. During a rear impact, a sensor senses the crash and pyrotechnically deploys a portion of the headrest toward the occupant. This system has the following potential problems:
1) An occupant can get a whiplash injury in fairly low velocity rear impacts; thus, either the system will not protect occupants in such accidents or there will be a large number of low velocity deployments with the resulting significant repair expense.
2) If the portion of the headrest which is propelled toward the occupant has significant mass, that is if it is other than an airbag type device, there is a risk that it will injure the occupant. This is especially true if the system has no method of sensing and adjusting for the position of the occupant.
3) If the system does not also have a system which pre-positions the headrest to the proximity of the occupant""s head, it will also not be affective when the occupant""s head is forward due to pre-crash braking, for example, or for different sized occupants.
A variation of this approach uses an airbag positioned in the headrest which is activated by a rear impact crash sensor This system suffers the same problems as the pyrotechnically deployed headrest portion. Unless the headrest is pre-positioned, there is a risk for the out-of-position occupant.
U.S. Pat. No. 5,833,312 to Lenz describes several methods for protecting an occupant from whiplash injuries using the motion of the occupant loading the seat back to stretch a canvas or deploy an airbag using fluid contained within a bag inside the seat back In the latter case, the airbag deploys out of the top of the seat back and between the occupant""s head and the headrest. The system is based on the proposed fact that xe2x80x9c[F]irstly the lower part of the body reacts and is pressed, by a heavy force, against the lower part of the seat back, thereafter the upper part of the body trunk is pressed back, and finally the back of the head and the head is thrown back against the upper part of the seat back . . . xe2x80x9d (Col. 2 lines 47-53). Actually this does not appear to be what occurs. Instead, the vehicle, and thus the seat that is attached to it, begins to decelerate while the occupant continues at its pre-crash velocity. Those parts of the occupant that are in contact with the seat experience a force from the seat and begin to slow down while other parts, the head for example continue moving at the pre crash velocity. In other words, all parts of the body are xe2x80x9cthrown backxe2x80x9d at the same time. That is, they all have the same relative velocity relative to the seat until acted on by the seat itself. Although there will be some mechanical advantage due to the fact that the area in contact with the occupant""s back will generally be greater than the area needed to support his or her head, there generally will not be sufficient motion of the back to pump sufficient gas into the airbag to cause it to be projected in between the head that is not rapidly moving toward the headrest. In some cases, the occupant""s head is very close to the headrest and in others it is far away. For all cases except when the occupant""s head is very far away, there is insufficient time for motion of the occupant""s back to pump air and inflate the airbag and position it between the head and the headrest. Thus, not only will the occupant impact the headrest and receive whiplash injuries, but it will also receive an additional impact from the deploying airbag.
Lenz also suggests that for those cases where additional deployment speed is required, that the output from a crash sensor could be used in conjunction with a pyrotechnic element. Since he does not mention anticipatory crash sensor, which were not believed to be available at the time of the filing of the Lenz patent application, it must be assumed that a conventional crash sensor is contemplated. As discussed herein, this is either too slow or unreliable since if it is set so sensitive that it will work for low speed impacts where many whiplash injuries occur, there will be many deployments and the resulting high repair costs. For higher speed crashes, the deployment time will be too slow based on the close position of the occupant to the airbag Thus, if a crash sensor is used, it must be an anticipatory crash sensor as disclosed herein.
It is an object of the present invention to provide new and improved headrests for seats in a vehicle which offer protection for an occupant in the event of a crash involving the vehicle.
It is another object of the present invention to provide new and improved seats for vehicles which offer protection for an occupant in the event of a crash involving the vehicle.
It is still another object of the present invention to provide new and improved cushioning arrangements for vehicles and protection systems including cushioning arrangements which provide protection for occupants in the event of a crash involving the vehicle.
It is yet another object of the present invention to provide new and improved cushioning arrangements for vehicles and protection systems including cushioning arrangements which provide protection for occupants in the event of a collision into the rear of the vehicle, i.e., a rear impact.
It is yet another object of the present invention to provide new and improved vehicular systems which reduce whiplash injuries from rear impacts of a vehicle by causing the headrest to be automatically positioned proximate to the occupant""s head.
It is yet another object of the present invention to provide new and improved vehicular systems to position a headrest proximate to the head of a vehicle occupant prior to a pending impact into the rear of a vehicle.
It is yet another object of the present invention to provide a simple anticipatory sensor system for use with an adjustable headrest to predict a rear impact.
It is yet another object of the present invention to provide a method and arrangement for protecting an occupant in a vehicle during a crash involving the vehicle using an anticipatory sensor system and a cushioning arrangement including a fluid-containing bag which is brought closer toward the occupant or ideally in contact with the occupant prior to or coincident with the crash. The bag would then conform to the portion of the occupant with which it is in contact.
It is yet another object of the present invention to provide an automatically adjusting system which conforms to the head and neck geometry of an occupant regardless of the occupant""s particular morphology to properly support both the head and neck.
Other objects and advantages of this invention will become apparent from the disclosure which follows.
In order to achieve at least one of the foregoing objects, a vehicle in accordance with the invention comprises a seat including a movable headrest against which an occupant can rest his or her head, an anticipatory crash sensor arranged to detect an impending crash involving the vehicle based on data obtained prior to the crash, and a movement mechanism coupled to the crash sensor and the headrest and arranged to move the headrest upon detection of an impending crash involving the vehicle by the crash sensor.
The crash sensor may be arranged to produce an output signal when an object external from the vehicle is approaching the vehicle at a velocity above a design threshold velocity. The crash sensor may be any type of sensor designed to provide an assessment or determination of an impending impact prior to the impact, i.e., from data obtained prior to the impact. Thus, the crash sensor can be an ultrasonic sensor, an electromagnetic wave sensor, a radar sensor, a noise radar sensor and a camera, a scanning laser radar and a passive infrared sensor.
To optimize the assessment of an impending crash, the crash sensor can be designed to determine the distance from the vehicle to an external object whereby the velocity of the external object is calculatable from successive distance measurements To this end, the crash sensor can employ means for measuring time of flight of a pulse, means for measuring a phase change, means for measuring a Doppler radar pulse and means for performing range gating of an ultrasonic pulse, an optical pulse or a radar pulse.
To further optimize the assessment, the crash sensor may comprise pattern recognition means for recognizing, identifying or ascertaining the identity of external objects. The pattern recognition means may comprise a neural network, fuzzy logic, fuzzy system, neural-fuzzy system, sensor fusion and other types of pattern recognition systems.
The movement mechanism may be arranged to move the headrest from an initial position to a position more proximate to the head of the occupant.
Optionally, a determining system determines the location of the head of the occupant in which case, the movement mechanism may move the headrest from an initial position to a position more proximate to the determined location of the head of the occupant. The determining system can include a wave-receiving sensor arranged to receive waves from a direction of the head of the occupant. More particularly, the determining system can comprise a transmitter for transmitting radiation to illuminate different portions of the head of the occupant, a receiver for receiving a first set of signals representative of radiation reflected from the different portions of the head of the occupant and providing a second set of signals representative of the distances from the headrest to the nearest illuminated portion the head of the occupant, and a processor comprising computational means to determine the headrest vertical location corresponding to the nearest part of the head to the headrest from the second set of signals from the receiver. The transmitter and receiver may be arranged in the headrest.
The head position determining system can be designed to use waves, energy, radiation or other properties or phenomena. Thus, the determining system may include an electric field sensor, a capacitance sensor, a radar sensor, an optical sensor, a camera, a three-dimensional camera, a passive infrared sensor, an ultrasound sensor, a stereo sensor, a focusing sensor and a scanning system.
A processor may be coupled to the crash sensor and the movement mechanism and determines the motion required of the headrest to place the headrest proximate to the head. The processor then provides the motion determination to the movement mechanism upon detection of an impending crash involving the vehicle by the crash sensor. This is particularly helpful when a system for determining the location of the head of the occupant relative to the headrest is provided in which case, the determining system is coupled to the processor to provide the determined head location.
A method for protecting an occupant of a vehicle during a crash in accordance with the invention comprises the steps of detecting an impending crash involving the vehicle based on data obtained prior to the crash and moving a headrest upon detection of an impending crash involving the vehicle to a position more proximate to the occupant. Detection of the crash may entail determining the velocity of an external object approaching the vehicle and producing a crash signal when the object is approaching the vehicle at a velocity above a design threshold velocity.
Optionally, the location of the head of the occupant is determined in which case, the headrest is moved from an initial position to the position more proximate to the determined location of the head of the occupant